Preheat your oven to 335°F (170°C). In a stand mixer, combine cake flour, sugar, baking powder, and salt until well mixed.

Add the softened unsalted butter and mix until the texture resembles coarse crumbs.

In a separate bowl, whisk together the buttermilk, eggs, and vanilla extract, then gradually incorporate this mixture into the dry ingredients, mixing until fluffy.

Divide the cake batter evenly among three greased 8-inch round cake pans.

Bake for about 30 minutes, or until a toothpick inserted comes out with a few moist crumbs.

Allow cakes to cool in the pans for 10 minutes before transferring to wire racks to cool completely.

Once cooled, carefully slice off the domed tops with a serrated knife to create flat layers.

Whisk mascarpone cheese, sugar, and vanilla extract until smooth.

Whip heavy cream until stiff peaks form, then gently fold into the mascarpone mixture.

Layer the cake by placing one layer on a plate, brushing with berry syrup, frosting, and topping with berries.

Repeat for the second layer, then finish with the third layer, frosting the outer layer and decorating with berries.

Let the cake rest for about 15-20 minutes before slicing and serving.